Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Optical fibers are widely used in fiber-optic communications, which may permit transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. In addition to light range frequencies providing substantially wider bandwidths than radio frequency (RF) range communications, optical fibers may be used instead of metal wires because signals may travel along them with less loss and may also be immune to electromagnetic interference. Lasers are preferred light sources (although other light sources may also be used) in a majority of fiber-optic communication systems.
Optical fibers may include a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by total internal reflection causing the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are often called multi-mode fibers, while those that support a single mode are often called single-mode fibers. Multi-mode fibers generally have a larger core diameter than single mode fibers, and thus multi-mode fibers may be used for short-distance communication links and for applications where high power may be transmitted.
From a fiber-type perspective, optical data communications can generally be categorized under two distinct approaches. One approach may include short-range, multi-mode, fiber-based solutions, which may provide a low cost solution for transmission of high bandwidth signals. Another approach may include long-range, single-mode, fiber-based solutions, which may result in a higher cost solution for transmission of signals. Some issues that may create the cost discrepancy may include a stringent alignment required by the single-mode fiber solutions, as well as the single-mode fibers being more suited to edge emitting lasers, which may be more expensive than vertical cavity lasers (VCSELs).